Cutting mechanism for rotary knife cutting machines

ABSTRACT

The present invention relates to rotary knife cutting machines which sever a roll of material wound on a core into plural narrower rolls by utilizing two rotary knives that are opposed to each other on opposite sides of the work-piece axis and by having knife feeding means that advances one of the knives into the workpiece by a fixed merement ahead of the other knife all during the working cut.

United States Patent [191 Judelson CUTTING MECHANISM FOR ROTY KNIFECUTTING MACHINES [75] Inventor: David N. Judelson, New York. NY.

[73] Assignee: Oscar I. .ludelshon Inc., New York,

221 Filedz Nov.6,1962

21 App1.No.:237,431

[62] Continuation of Ser. No. sosrT/iu tnj 'l'ci'i ai.

[52] US. Cl. 82/86 R, 82/53 R [51] Int. Cl B23b 3/04, B23b 5/14, 1323b37/00 [58] Field of Search 82/46, 86, 101

[56] References Cited UNITED STATES PATENTS 2,457,310 Judelson 80/86Aug. 1, 1973 2,015,877 10/1935 Thompson 82/46 X 1,098,167 5/1914 Potten82/98 X 1,372,127 3/1921 Faunce 82/92 Primary Examiner-Harrison L.l-linson Attorney-Amster and Rothstein [5 7] ABSTRACT The presentinvention relates to rotary knife cutting machines which sever a roll ofmaterial wound on a core into plural narrower rolls by utilizing tworotary knives that are opposed to each other on opposite sides of thework-piece axis and by having knife feeding means that advances one ofthe' knives into the workpiece by a fixed merement ahead of the otherknife all during the working cut.

9 Claims, 3 Drawing Figures Patented Aug. 14, 1973 3,752,024

mmvroa DAVID M Juousow 9/ F IG. 2

Afro/avers CUTTING MECHANISM FOR ROTARY ENTEE CUTTING MACHINES This is acontinuation of U.S. Pat. application Ser. No. 50,917 filed on Aug. 22,1960 Pat. No. 3,700,402 and entitled Cutting Mechanism for Rotary KnifeCutting Machines."

The present invention relates generally to rotary knife cutting machineswhich are adapted to sever a roll of material wound on a core intoplural strips, and in particular to mechanisms for cutting relativelydense rolls of material, such as relatively thin polyethylene and likethin films of plastic, which when wound into a roll exhibits a highorder of hardness.

In a typical rotary knife cutting machine, such as disclosed in U.S.Pat. No. 2,457,310 of Dec. 28, 1948 and in pending application Ser. No.722,301 filed Mar. l8, 1958, both said patent and application beingassigned to the assignee of the present invention, there is disclosed arotary knife cutting machine which enables the automatic or manualcutting of a roll of material into a number of strips of a prescribedwidth. A typical machine includes a frame upon which is supported astationary shaft which receives the roll of material wound on a core andusually enclosed within a paper wrap.

-The roll of material is rotated about the longitudinal shaft axis bymeans of a chuck which engages one end of the roll and is driven from anappropriate variable high speed drive. A high speed rotary knife ismounted on a knife carrier and is movable toward and away from thestationary supporting shaft. The carrier in turn is mounted on themovable carriage which has an indexing mechanism selectively engageablewith the frame of the machine such that the carriage may be movedstepwise through a prescribed and adjustable traversing stroke formoving the carrier and the rotary knife into successive indexed cuttingpositions along the length of the machine toward the chucked end of theroll of material. After each stepwise advance of the carriage, the knifecarrier is actuated, either automatically or manually, to move therotary knife inwardly toward the stathrough the roll of material and itscore to sever the same into tapes or ribbons.

Such rotary knife cutting machines maybe employed to cut relative denserolls of material, such as of thin polyethylene film and the like, byemploying a twostage operation. After a roll is placed upon thestationary shaft and turned at the prescribed speed, the first stageinvolves employing a rotary sawing blade to cut through the material andthrough the core. Rolls cut with such sawing blade have successive endcut faces defining opposite sides of the strips or ribbons, which arerough and irregular. Often, unless caution is exercised, there is atendency for such rough end faces of the strips or ribbons to fuse dueto the heat developed incident to the action of the sawing blade as itpenetrates radially inwardly through the roll towards the core in itscutting stroke. After this initial rough cutting or sawing, the secondstage involves the taking of a trim cut with a trimming blade to providerelatively smooth cut end faces defining opposite sides of the strips orribbons. Here again care must be taken to rotate the trimming knife andto penetrate at a rate such as to avoid the tendency to fuse the cut endfaces of the roll. Necessarily such two-stage operation istime-consuming, comparatively expensive, and wasteful of material.

It has been suggested that the two stages may be achieved concurrentlyin a rotary knife cutting machine by arranging the sawing and trimmingknives or blades at approximately l8(Y circumferentially of the roll ofmaterial such that the sawing and trimming may occur simultaneously. Onesuggested system involves the mounting of the trimming knife or bladewhich includes two bevelled trimming edges having a pneumatic controland to similarly mount the sawing knife or blade on an independentlypivoted arm with an independent pneumatic control. The sawing blade isarranged radially outwardly in relation to the trimming blade and theblades advance simultaneously through the cutting stroke toward the coresuch that the sawing blade lags throughout the cutting stroke. As thetrimming blade moves forwardly and penetrates the roll of material, areaction force is developed by the roll of material; and periodicallythe trimming blade will tend to stop in its forward motion due to suchreaction force.

Concurrently, the lagging sawing blade cuts away the material removedinitially by the trimming blade; and once the accumulation of cutmaterial is removed, the operation may go. forwardly with the trimmingblade making a further forward penetration into the roll of material.This proposed system is inherently fraught with difficulty since itrequires for its operation the development of a reaction force or backpressure on the trimming blade which reaction force or back pressurecauses the development of heat with the attendant risk of fusing the cutedges of the plastic material. Further,

it is difficult to establish optimum cutting conditions with any degreeof flexibility as is required to handle various types of plasticmaterials and rolls of varying density and diameter.

Broadly, it is an object of the present invention to provide an improvedcutting mechanism which obvi ates one or more of the aforesaiddifficulties. Specifically, it is within the contemplation of thepresent invention to provide a cutting system for relatively dense rollsof plastic and like materials in which sawing and trimming operationsoccur simultaneously, with the trim taken from the roll by the trimmingblade being thrown into the cut made by the sawing blade such that thetrimmed material is comminutedand the cut is kept relatively free ofclogging.

It is a further object of the present invention to establish individualspeeds of rotation for the sawing and trimming knives or blades such asto permit the establishment of optimum cutting conditions for varyingtypes of materials, roll densities and roll diameters.

In accordance with an illustrative embodiment demonstrating objects andfeatures of the present inven- I tion, there is provided a cuttingmechanism for cutting a roll of material into a plurality of tapes whichcomprises a supporting frame, a rotary sawing blade or knife having asawing edge, and a rotary trimming blade or knife having a trimmingedge. The blades are disposed substantially in a common cutting plane atright angles to the longitudinal axis of the roll of mate rial and itssupporting shaft. Carrier means mount the blades on the supported framefor movement through a cutting stroke in the common cutting plane from aretracted position spaced from the longitudinal axis of 'the roll ofmaterial to an advanced position contiguous thereto. The sawing edge isdisposed radially inwardly of the trimming edge by a fixed incrementsuch that the sawing edge leads the trimming edge as the roll ofmaterial is cut. Provision is made for turning the blades at desiredsawing and trimming speeds which advantageously may be made independentof each other, with the sawing blade preferably being turned at a lowerrate of speed to develop a relatively low order of heat incident to theinitial rough cutting action. As the sawing proceeds, the trimmedmaterial taken from the opposite rough cut faces of the saw cut arethrown into such saw cut wherein the trimmed material is comminutedthereby keeping the cut relatively free of clogging and permitting theuniform advance of the blades through the forward cutting stroke.

The above brief description, as well as other objects and features andadvantages of the present invention will be more fully appreciated byreference to thefollowing detailed description of a presently preferred,but nonetheless illustrative embodiment according to the presentinvention, when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a fragmentary plan view of a typical rotary knife cuttingmachine embodying cutting mechanisms in accordance with the presentinvention;

FIG. 2 is a sectional view taken substantially along the line 2-2 ofFIG. 1 in the direction of the arrows, and on a somewhat large scale,showing details of the cutting mechanism; and,

FIG. 3 is a sectional view taken substantially along the line 33 of FIG.2 in the direction of the arrows, with parts broken away to show theconcurrent sawing and trimming action achieved in accordance with thepresent invention.

Referring now specifically to the drawings, abrief description will beset forth of portions of a typical rotary knife cutting machine,generally designated by the reference numeral 10, to illustrate theenvironment for a cutting mechanism in accordance with the presentinvention. For further details of a manual machine suitable for thepractice of the present invention, reference may be made to US. Pat. No.2,457,310; and for details of an automatic machine, reference may bemade to said pending US. Pat. application, Ser. No. 722,301. The machineincludes a frame or support having an upright standard 12 at one endthereof from which projects the longitudinally extending stationarysupporting shaft 14 which has a flat 14a on one side and which receivesthe roll of material R wound on a core C, as of cardboard, (see FIG. 2).The roll R is adapted to be cut into plural strips or ribbons S on amanual or automatic basis. One end of the roll of material R is broughtinto abutment with a chuck 16 which is of the type including a number ofroll-penetrating elements which may be engaged into the outer peripheryof the roll R for fixing the same, with one end thereof against theadjacent end face of the chuck plate 20. For a detailed description ofan improved chuck 16 which may be employed in the present machine,reference may be made to U.S. Pat. No. 2,938,733 of May 31, 1960,assigned to the assignee herein. As seen in FIG. 1, the chuck I6 isrotated about the stationary roll-supporting shaft 14 at the prescribedroll turning speed by a variable speed drive motor 22 which is mountedon an appropriate support provided by the machine frame. The drive shaft220 of the motor 22 is coupled to the chuck 16 by a belt and pulleycoupling, including the pulley 24 on the motor shaft 220, the pulley 26on the chuck 16 and the belt 28 trained over the pulleys 24, 26. Thebelt and pulley coupling is arranged to achieve the required speedreduction between the motor shaft 22a and the chuck 16.

Mounted on the machine frame is the improved cutter assembly of thepresent invention, generally designated by the reference numeral 30,which includes a knife carriage or mount 32 which is movable along themachine frame in a path parallel to the longitudinal axis of theroll-supporting shaft 14 and on appropriate guide rail 34, 36 extendingthrough the bearings 38, 40, 42 and 44 on the knife carriage 32. Theknife carriage 32 is moved longitudinally of the machine frame throughsuccessive longitudinal traversing incuments or strokes to bring thehigh speed rotary sawing and trimming knives into successive positionsincutting planes at right angles to the roll-supporting shaft 14, eithermanually or automatically, as described in US. Pat. No. 2,457,310 andsaid copending application Ser. No. 722,301.

Disposed within a common cutting plane and extending at right angles tothe roll-supporting shaft 14, which cutting plane may be progressivelyadvanced along the length of the roll R, are a rotary sawing blade orknife 46 and a rotary trimming blade or knife 48. As seen best in FIG.2, the sawing knife 46 is below the roll R and the trimming knife 48 isabove the roll R. The respective knives are circumferentially spaced atapproximately relative to each other. The sawing knife 46 is providedwith circumferential or peripheral sawing teeth 50 of an appropriateconfiguration to take a relatively rough sawing cut SC through the rollof material, as shown in FIG. 3; while the trimming blade 48 is providedwith a V-shaped circumferential or peripheral notch 52 defining bevelledtrimming edges 52a, 52b, which meet at an apex 54 inwardly of the outerperiphery of the knife 48. As best seen in the enlarged showing of FIG.3, the trimming knife 48 is of a greater width than the sawing knife 46,with median lines through the knives 46, 48 being arranged symmetricallyabout a common plane and with the outer faces 48a, 48b, of the trimmingknife 48 being respectively disposed outwardly of the adjacent outerfaced 46a, 46b of the sawing knife 46 for making a wider trimming cutTC. The sawing edge 50- of the sawing knife or blade 46 is disposedradially inwardly of the bevelled trimming surfaces 52a, 52b of thetrimming knife 48 such that as the knives 46, 48, concurrently penetratethe roll of material R with a fixed interval or increment therebetween,the leading sawing knife {36 makes the narrow sawing cut or groove SCwhich is followed up by the somewhat wider and symmetrical disposedtrimming cut TC. With this arrangement, there is substantially notendency for the sawing cut SC to clog up due to the accumulation ofsawings from the roll R in that such accumulation is chewed up orcomminuted by the action of the trimming knife 48.

In order to mount the rotary sawing and trimming knifes 46, 48 on theknife carriage 32, there is provided a pair of upstanding mountingplates 58, 60 which extend at right angles to the guide rails 34, 36 Andare welded or otherwise secured to the knife carriage 32. Extendingtransversely of the upstanding mounting plates 58, 60 are lower andupper mounting studs 62, 64 which are joumaled in the mounting plates58, 60 and provide respective pivotal mounts for the sawing knifecarrier 66 and the trimming knife carrier 68. Since the knife carriers66, 68 are disposed one above the other in a common vertical cuttingplane, the trimming knife carrier 68 is only visable when the machine isview from above as shown in FIG. 1. The sawing knife carrier 66 includesa mounting bearing 70 on the end thereof remote from the sawing knife 46which bearing 70 is journaled about the axis provided by the lowermounting stud 62. At its end remote from the mounting bearing 70, theknife carrier 66 is provided with a knife-supporting bearing 72 (see thedotted line shown in FIG. 2) through which extends the sawing knifeshaft 74 'which is fixed at one end to the sawing knife 46 and is drivenfrom its other end, as will subsequently be described. In a similarfashion the trimming knife carrier 68 is provided with a mountingbearing 76 at the end thereof remote from the trimming knife 68 whichmounting bearing 76 is journaled on the upper mounting stud 64. At itsend remote from the mounting bearing 76, the trimming knife carrier 68is provided with a knife-supporting bearing 78 (seen in FIG. 1) throughwhich extends the trimming knife shaft 80 which is fixed at one end tothe trimming knife 48 and is driven from its opposite end, as willsubsequently be described.

The sawing and trimming knives 46, 48 are moved through their forward orcutting stroke in the cutting cycle of the machine and in the requiredradial rela-' tionship by the provision of a driven gear sector 82 onthe sawing knife carrier 66 which is in meshing engagement with afollower gear sector 84 on the trimming knife carrier 68. By appropriateinitial positioning of the knives 46, 48 and selection of theintermeshing relationship between driven gear sector 82 and the followergear sector 84, it is possible to arrange the sawing knife 46 to leadthe trimming knife 48 by a prescribed fixed increment over the entireoperative portion or stroke in the cutting cycle. In this illustrativearrangement, the driven gear sector 82 is turned to bring about the inunison advance of the knives 46, 48 by a manual arrangement whichincludes a driving gear 86 which is journaled on a gear stud 88extending between the upstanding mounting plates 56, 58, which drivinggear 86 is turned by an actuating shaft 90 through a hand wheel 92.Although a manual arrangement is shown for moving the knives 46, 48through the cutting stroke, it will be appreciated that it is within thecontemplation of the invention to actuate the knives 46, 48 by otherappropriate manual arrangements, as well as by the automatic mechanismdisclosed in said copending US. Pat. application, Ser. No.722,301.

Independent drives are provided for the respective sawing and trimmingknives 46, 48 such that desired knife speeds may be established inaccordance withthe type of material being cut. The trimming knife driveincludes a variable speed drive motor 94 which is mounted on the knifecarriage 32. A belt and pulley coupling is arranged between the motorshaft 94a and the knife shaft 80. Specifically, the upper mounting stud64 is projected outwardly of the mounting plate 60 to serve as a pulleyshaft on which there is fixed an intermediate driven pulley 96. Thedriven pulley 96 is coupled to a drive pulley 98 on the motor shaft 94aby a belt 100. The driven pulley 96 in turn is fixed to a furtherintermediate pulley 102 which is coupled by a belt 104 to a knife pulley106 fixed to the knife shaft 80. In a similar fashion an independentdrive is provided for the sawing knife 46 which includes a drive motor108 having its motor shaft 108a coupled by driving pulley 110 and a belt112 to an intermediate pulley 114 on the lower mounting stud 62 whichserves as a pulley shaft. The intermediate pulley 114 is connected to afurther intermediate pulley 116 which in turn is connected by a belt 118to a knife pulley 120 fixed to the knife shaft 74 (see FIG. 4).

In order to facilitate a more thorough understanding of the presentinvention, reference will now be made to a typical sequence of cuttingin accordance with the present invention:

After the machine operator places the roll of material R on the machineand engages the same with the chuck 16, the machine is placed inoperation. The knife carriage 32 is indexed to the'appropriate positionlongitudinally of the machine to orient the coplanar sawing and trimmingknives 46, 48 to take a cut transversely through the roll R towards thecore C thereof. Such indexing may be in accordance with the principlesof issued patents assigned to the assignee of the present invention orin accordance with the teachings of said copending U.S. Pat. applicationSer. No. 722,301. Thereupon the sawing and trimming knives 46, 48 aremoved inwardly through their cutting strokes, with the sawing edge Slllof the sawing knife 46 leading the bevelled surfaces 52a, 52b of thetrimming edge 52 of the trimming knife 48. The cutting progresses untilsuch as the sawing edge penetrates through the core C and approaches theflat 14a on the roll-supporting shaft 14. It will be appreciated thatonly one flat is required on the roll-supporting shaft 14 opposite thepoint of penetration of the sawing knife 46 in that the laggingrelationship of the trimming knife 48 precludes the possibility ofcontact with the shaft. During the cutting operation, which progressesat a substantially uniform rate as established by the motion-imparted tothe carriers 66, 68, the sawing knife 46 takes the rough cut SC,followed by the fine cut TC of the trimming knife 48, with cloggingbeing effectively precluded due to the comminuting action of thetrimming knife 48. At the end of the cut, the knives 46, 48 areretracted to a clearance position relative to the roll, the knifecarriage is indexed, and the operation .is repeated.

A latitude of modification, change and substitution is intended in theforegoing disclosure and in some instances some features of theinvention will be employed without a corresponding use of otherfeatures. Accord- I ingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with;the spirit and scopeof the invention herein.

What I claim is:

1. A cutting mechanism for cutting a roll of material into plural tapescomprising a support, a rotary sawing blade having a sawing edge, arotary trimming blade having a trimming edge, said blades being disposedsubstantially in a common plane at right angles to the longitudinal axisof said roll and substantially in opposed relation to each other,carrier means mounting said blades on said support for movement througha cutting stroke in said common plane from a retracted position spacedfrom said longitudinal axis to an advanced position contiguous thereto,said sawing edge being disposed radially inwardly of said trimming edgeby a fixed increment such that said roll of material is first cut bysaid sawing blade and then trimmed by said trimming blade during saidcutting stroke, and means operatively connected to said sawing blade andto said trimming blade for rotating said blades.

2. A cutting mechanism according to claim 1 wherein said trimming bladeis of a greater width than said sawing blade.

3. A cutting mechanism for a cutting machine including a support, ashaft on said support adapted to receive a roll of material and a chuckfor rotating said roll of material comprising a rotary sawing bladehaving a sawing edge, a rotary trimming blade having a trimming edge,said blades being disposed substantially in a common cutting plane atright angles to the longitudinal axis of said stationary shaft andsubstantially in opposed relation to each other, carrier means mountingsaid blades on said support for movement through a cutting stroke insaid common cutting plane from a retracted position spaced from saidstationary shaft to an advanced position contiguous to said shaft, saidsawing edge being disposed radially inwardly of said trimming edge suchthat said roll of material is first cut by said sawing blade and thentrimmed by said trimming blade during said cutting stroke, saw-rotatingmeans operatively connected to said sawing blade, and trim-rotatingmeans operatively connected to said trimming blade.

4. in a cutting machine, a support, a stationary shaft on said supportadapted to receive a roll of material, a chuck for rotating said roll ofmaterial, and cutting mechanisms for cutting said roll of material intoplural tapes, the improvement comprising said cuttingmechanisms-including a rotary sawing blade having a sawing edge, arotary trimming blade having a trimming edge, said blades being disposedsubstantially in a common cutting plane at right angles to the axis ofsaid stationary shaft and substantially in opposed relation to eachother, carrier means mounting said blades on said support for movementthrough a cutting stroke in said common cutting plane from a retractedposition spaced from said stationary shaft to an advanced positioncontiguous to said shaft, said sawing edge being disposed radiallyinwardly of said trimming edge by a fixed increment such that said rollof material is first cut by said sawing blade and then trimmed by saidtrimming blade during said cutting stroke, and means operativelyconnected to said sawing blade and to said trimming blade for rotatingsaid blades.

5. In a rotary knife cutting machine, a frame including a knife mount,roll-supporting and turning means on said frame including a shaftadapted to receive and support a roll of material which is to be cutinto a plurality of tapes while turning about the shaft axis, a sawingknife carrier mounted on said knife mount for movement toward and awayfrom said shaft, a rotary sawing knife having a sawing edge mounted onsaid sawing knife carrier for rotation about a sawing axis parallel tosaid shaft axis, a trimming knife carrier mounted on said knife mountfor movement toward and away from said shaft, a rotary trimming knifehaving a trimming edge mounted on said trimming knife carrier forrotation about a trimming axis parallel to said shaft axis, said sawingand trimming knives being disposed in opposed relation to each other andin a common cutting plane extending at right angles to said shaft axis,said sawing edge being disposed radially inwardly of said trimming edgeby a fixed increment such that said roll of material is first cut bysaid sawing knife and then trimmed by said trimming knife duringmovement of said knives toward said shaft, means operatively connectedto said sawing and trimming knife carriers for moving said sawing andtrimming knives toward said shaft during a cutting stroke whilemaintaining said fixed increment between said sawing and trimming edges,and means operatively connected to said knives for rotating said knives.

6. In a rotary knife cutting machine according to claim 5, said trimmingknife being of a greater width than said sawing knife such as to trimadjacent faces of said roll of material after cutting said said sawingknife.

7. In a rotary knife cutting machine, a frame, rollsupporting andturning means on said frame including a stationary shaft adapted toreceive and support a roll of material which is to be cut into aplurality of tapes while turning about the shaft axis, a knife carriage,means mounting said knife carriage on said frame for longitudinaltraverse along a path parallel to said shaft axis, a sawing knifecarrier mounted on said knife carriage for movement toward and away fromsaid stationary shaft, a rotary sawing knife having a sawing edgemounted on said sawing knife carrier for rotation about a sawing axisparallel to said shaft axis, a trimming knife carrier mounted on saidknife carriage for movement toward and away from said stationary shaft,a rotary trimming knife having a trimming edge mounted on said trimmingknife carrier for rotation about a trimming axis parallel to said shaftaxis, said sawing and trimming knives being disposed in a common cuttingplane extending at right angles to said shaft axis, said sawing edgebeing disposed radially inwardly of said trimming edge such that saidroll of material is first cut by said sawing knife and then trimmed bysaid trimming knife during movement of said knives toward saidstationary shaft, means operatively connected to said sawing andtrimming knife carrier for moving said sawing and trimming knives towardand away from said stationary shaft during a cutting cycle whilemaintaining the radial relationship between said sawing and trimmingedges, means operatively connected to said sawing knife for rotatingsaid knife at a sawing speed, and separate means operatively connectedto said trimming knife for rotating said trimming knife at a trimmingspeed.

8. A cutting mechanism for use in a rotary knife cutting machineincluding a frame, roll-supporting and turning means on said frameincluding a stationary shaft adapted to receive and support a roll ofmaterial which is to be cut into a plurality of tapes while turningabout the shaft axis, a knife carriage and means mounting said knifecarriage on said frame for longitudinal traverse along a path parallelto said shaft axis, said cutting mechanism including a sawing knifecarrier adapted to be pivotally mounted on said knife carriage formovement toward and away from said stationary shaft, a rotary sawingknife having a sawing edge rotatably mounted on said sawing knifecarrier for rotation about a sawing axis parallel to said shaft axis, atrimming knife carrier adapted to be pivotally mounted on said knifecarriage for movement toward and away from said stationary shaft, arotary trimming knife having a trimming edge rotatably mounted on saidtrimming knife carrier for rotation about a trimming axis parallel tosaid shaft axis, said sawing and trimming knives being disposed inopposed relation to each other in a substantially common plane extendingat right angles to said shaft axis, said sawing edge being disposedradially inwardly of said trimming edge by a fixed increment and beingof a lesser width then said trimming edge such that said roll ofmaterial is first cut by said blades on said support for movementthrough a cutting stroke in said common plane from a retracted positionspaced from said longitudinal axis to an advanced position contiguousthereto, said sawing edge being disposed radially inwardly of saidtrimming edge by a fixed increment such that said roll of material isfirst cut by said sawing blade and then trimmed by said trimming bladeduring said cutting stroke, and power means for driving one of saidblades.

l 8 IF i

1. A cutting mechanism for cutting a roll of material into plural tapescomprising a support, a rotary sawing blade having a sawing edge, arotary trimming blade having a trimming edge, said blades being disposedsubstantially in a common plane at right angles to the longitudinal axisof said roll and substantially in opposed relation to each other,carrier means mounting said blades on said support for movement througha cutting stroke in said common plane from a retracted position spacedfrom said longitudinal axis to an advanced position contiguous thereto,said sawing edge being disposed radially inwardly of said trimming edgeby a fixed increment such that said roll of material is first cut bysaid sawing blade and then trimmed by said trimming blade during saidcutting stroke, and means operatively connected to said sawing blade andto said trimming blade for rotating said blades.
 2. A cutting mechanismaccording to claim 1 wherein said trimming blade is of a greater widththan said sawing blade.
 3. A cutting mechanism for a cutting machineincluding a support, a shaft on said support adapted to receive a rollof material and a chuck for rotating said roll of material comprising arotary sawing blade having a sawing edge, a rotary trimming blade havinga trimming edge, said blades being disposed substantially in a commoncutting plane at right angles to the longitudinal axis of saidstationary shaft and substantially in opposed relation to each other,carrier means mounting said blades on said support for movement througha cutting stroke in said common cutting plane from a retracted positionspaced from said stationary shaft to an advanced position contiguous tosaid shaft, said sawing edge being disposed radially inwardly of saidtrimming edge such that said roll of material is first cut by saidsawing blade and then trimmed by said trimming blade during said cuttingstroke, saw-rotating means operatively connected to said sawing blade,and trim-rotating means operatively connected to said trimming blade. 4.In a cutting machine, a support, a stationary shaft on said supportadapted to receive a roll of material, a chuck for rotating said roll ofmaterial, and cutting mechanisms for cutting said roll of material intoplural tapes, the improvement comprising said cutting mechanismsincluding a rotary sawing blade having a sawing edge, a rotary trimmingblade having a trimming edge, said blades being disposed substantiallyin a common cutting plane at right angles to the axis of said stationaryshaft and substantialLy in opposed relation to each other, carrier meansmounting said blades on said support for movement through a cuttingstroke in said common cutting plane from a retracted position spacedfrom said stationary shaft to an advanced position contiguous to saidshaft, said sawing edge being disposed radially inwardly of saidtrimming edge by a fixed increment such that said roll of material isfirst cut by said sawing blade and then trimmed by said trimming bladeduring said cutting stroke, and means operatively connected to saidsawing blade and to said trimming blade for rotating said blades.
 5. Ina rotary knife cutting machine, a frame including a knife mount,roll-supporting and turning means on said frame including a shaftadapted to receive and support a roll of material which is to be cutinto a plurality of tapes while turning about the shaft axis, a sawingknife carrier mounted on said knife mount for movement toward and awayfrom said shaft, a rotary sawing knife having a sawing edge mounted onsaid sawing knife carrier for rotation about a sawing axis parallel tosaid shaft axis, a trimming knife carrier mounted on said knife mountfor movement toward and away from said shaft, a rotary trimming knifehaving a trimming edge mounted on said trimming knife carrier forrotation about a trimming axis parallel to said shaft axis, said sawingand trimming knives being disposed in opposed relation to each other andin a common cutting plane extending at right angles to said shaft axis,said sawing edge being disposed radially inwardly of said trimming edgeby a fixed increment such that said roll of material is first cut bysaid sawing knife and then trimmed by said trimming knife duringmovement of said knives toward said shaft, means operatively connectedto said sawing and trimming knife carriers for moving said sawing andtrimming knives toward said shaft during a cutting stroke whilemaintaining said fixed increment between said sawing and trimming edges,and means operatively connected to said knives for rotating said knives.6. In a rotary knife cutting machine according to claim 5, said trimmingknife being of a greater width than said sawing knife such as to trimadjacent faces of said roll of material after cutting said said sawingknife.
 7. In a rotary knife cutting machine, a frame, roll-supportingand turning means on said frame including a stationary shaft adapted toreceive and support a roll of material which is to be cut into aplurality of tapes while turning about the shaft axis, a knife carriage,means mounting said knife carriage on said frame for longitudinaltraverse along a path parallel to said shaft axis, a sawing knifecarrier mounted on said knife carriage for movement toward and away fromsaid stationary shaft, a rotary sawing knife having a sawing edgemounted on said sawing knife carrier for rotation about a sawing axisparallel to said shaft axis, a trimming knife carrier mounted on saidknife carriage for movement toward and away from said stationary shaft,a rotary trimming knife having a trimming edge mounted on said trimmingknife carrier for rotation about a trimming axis parallel to said shaftaxis, said sawing and trimming knives being disposed in a common cuttingplane extending at right angles to said shaft axis, said sawing edgebeing disposed radially inwardly of said trimming edge such that saidroll of material is first cut by said sawing knife and then trimmed bysaid trimming knife during movement of said knives toward saidstationary shaft, means operatively connected to said sawing andtrimming knife carrier for moving said sawing and trimming knives towardand away from said stationary shaft during a cutting cycle whilemaintaining the radial relationship between said sawing and trimmingedges, means operatively connected to said sawing knife for rotatingsaid knife at a sawing speed, and separate means operatively connectedto said trimming knife for rotating said trimming knife at a trimmingspeed.
 8. A cutting mechanism for use in a rotary knife cutting machineincluding a frame, roll-supporting and turning means on said frameincluding a stationary shaft adapted to receive and support a roll ofmaterial which is to be cut into a plurality of tapes while turningabout the shaft axis, a knife carriage and means mounting said knifecarriage on said frame for longitudinal traverse along a path parallelto said shaft axis, said cutting mechanism including a sawing knifecarrier adapted to be pivotally mounted on said knife carriage formovement toward and away from said stationary shaft, a rotary sawingknife having a sawing edge rotatably mounted on said sawing knifecarrier for rotation about a sawing axis parallel to said shaft axis, atrimming knife carrier adapted to be pivotally mounted on said knifecarriage for movement toward and away from said stationary shaft, arotary trimming knife having a trimming edge rotatably mounted on saidtrimming knife carrier for rotation about a trimming axis parallel tosaid shaft axis, said sawing and trimming knives being disposed inopposed relation to each other in a substantially common plane extendingat right angles to said shaft axis, said sawing edge being disposedradially inwardly of said trimming edge by a fixed increment and beingof a lesser width then said trimming edge such that said roll ofmaterial is first cut by said sawing knife and then trimmed by saidtrimming knife during movement of said knives toward said stationaryshaft, and means for rotating said knives.
 9. A cutting mechanism forcutting a roll of material into plural tapes comprising; a support, arotary sawing blade having a sawing edge, a rotary trimming blade havinga trimming edge, said blades being disposed substantially in a commonplane at right angles to the longitudinal axis of said roll andsubstantially in opposed relation to each other, carrier means mountingsaid blades on said support for movement through a cutting stroke insaid common plane from a retracted position spaced from saidlongitudinal axis to an advanced position contiguous thereto, saidsawing edge being disposed radially inwardly of said trimming edge by afixed increment such that said roll of material is first cut by saidsawing blade and then trimmed by said trimming blade during said cuttingstroke, and power means for driving one of said blades.